As you progress through Pokemon Scarlet and Violet, you’ll encounter an increasing number of Gym Leaders, Titans, and Team Star bases in order to complete the main story. Whatever path you take, you’ll eventually come across the False Dragon Titan, a massive Dragon-Type Pokemon that lives on an island.
There are two major points to consider before tackling this Titan. The first is to make this your fourth or fifth Titan. It is, along with the Quaking Earth Titan, the most difficult Titan in the game and will easily wipe out your party if you are under-leveled. Your party should aim for a level of 50 or higher. The second point is to ensure that Koraidon/swim Miraidon’s ability is unlocked. After defeating your second Titan, you’ll be able to swim. Because the False Dragon Titan is in the middle of a large lake, having this ability will be extremely useful.
With that out of the way, you’re ready to track down the Titan. Follow your map to the False Dragon Titan icon until you reach the far-right island in Casseroya Lake. However, when you arrive on the island, you will not immediately encounter any Titans. Instead, there will be a swarm of small fish on the surface, followed by a brief message from Arven. He’ll complain that finding the Titan is difficult and that he wishes someone would just yell the answer.
You may notice that the small fish have small pop-up phrases above their heads as you walk around the small island. You’ll notice an orange pokemon yelling, “Taitaan!” as you walk around. That’s correct. Titan is yelling. When you interact with this fish, Dondozo, the False Dragon Titan, will appear shortly after.
Your Titan battle will begin once Dondozo appears! Unlike previous battles, this one has three phases, so make sure you have plenty of powerful Pokemon and items to aid you!